Perhaps if one used a Russian battery with a certain isotope. Of course the user would probably expire before the battery!
Seriously, the biggest bottleneck in the portable domain by far is storage. A SMP system would just be waiting for data. There may be support for HT in the future, but it would still have the issue with increased power consumption. When 10GB+ 2.5" profile SSD drives come out, perhaps this will change.
Cheers!